Hello,
I'd like to ask your opinion on this change; I think it should be reverted or at least made silent by default. Basically, it prints a warning like
gc: 2 uncollectable objects at shutdown: Use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them.
at interpreter shutdown if gc.garbage is nonempty.
I would like to piggy-back on this discussion to suggest further warnings (either by default, or switchable). One feature I've often considered would be to add a warning in FileIO and socket dealloc if these objects haven't been closed explicitly. In most situations, relying on garbage collection to shutdown OS resources (here, file descriptors) is something we like to discourage. Furthermore, it can produce real bugs, especially under Windows when coupled with refererence cycles created by traceback objects (the random test_tarfile failures on the Windows buildbots were a symptom of that; their cause would have been obvious with such warnings). What do you think? Antoine.